1. Field of the Invention
The present invention generally relates to database development using computer aided design and, more particularly, to manipulating data from any environment in the world (e.g. cities, buildings, campuses, floors within a building, objects in an outdoor setting, etc.) to construct an electronic building database that can be used to generate definitions of the user""s building and site parameters and used with wireless communication system modeling and engineering planning products.
2. Background Description
As wireless communications use increases, radio frequency (RF) coverage within buildings and signal penetration into buildings from outside transmitting sources has quickly become an important design issue for wireless engineers who must design and deploy cellular telephone systems, paging systems, or new wireless systems and technologies such as personal communication networks or wireless local area networks. Designers are frequently requested to determine if a radio transceiver location, or base station cell site can provide reliable service throughout an entire city, an office, building, arena or campus. A common problem for wireless systems is inadequate coverage, or a xe2x80x9cdead zone,xe2x80x9d in a specific location, such as a conference room. It is now understood that an indoor wireless PBX (private branch exchange) system or wireless local area network (WLAN) can be rendered useless by interference from nearby, similar systems. The costs of in-building and microcell devices which provide wireless coverage within a 2 kilometer radius are diminishing, and the workload for RF engineers and technicians to install these on-premises systems is increasing sharply. Rapid engineering design and deployment methods for microcell and in-building wireless systems are vital for cost-efficient build-out.
Analyzing radio signal coverage penetration and interference is of critical importance for a number of reasons. A design engineer must determine if an existing outdoor large scale wireless system, or macrocell, will provide sufficient coverage throughout a building, or group of buildings (i.e., a campus). Alternatively, wireless engineers must determine whether local area coverage will be adequately supplemented by other existing macrocells, or whether indoor wireless transceivers, or picocells, must be added. The placement of these cells is critical from both a cost and performance standpoint. If an indoor wireless system is being planned that interferes with signals from an outdoor macrocell, the design engineer must predict how much interference can be expected and where it will manifest itself within the building, or group of buildings. Also, providing a wireless system that minimizes equipment infrastructure cost as well as installation cost is of significant economic importance. As in-building and microcell wireless systems proliferate, these issues must be resolved quickly, easily, and inexpensively, in a systematic and repeatable manner.
There are many computer aided design (CAD) products on the market that can be used to design the environment used in one""s place of business or campus. WiSE from Lucent Technology, Inc., SignalPro from EDX, PLAnet by Mobile Systems International, Inc., and TEMS and TEMS Light from Ericsson are examples of wireless CAD products. In practice, however, a pre-existing building or campus is designed only on paper and a database of parameters defining the environment does not readily exist. It has been difficult, if not generally impossible, to gather this disparate information and manipulate the data for the purposes of planning and implementation of indoor and outdoor RF wireless communication systems, and each new environment requires tedious manual data formatting in order to run with computer generated wireless prediction models. Recent research efforts by ATandT Laboratories, Brooklyn Polytechnic, and Virginia Tech, are described in papers and technical reports entitled xe2x80x9cRadio Propagation Measurements and Prediction Using Three-dimensional Ray Tracing in Urban Environments at 908 MHZ and 1.9 GHz,xe2x80x9d (IEEE Transactions on Vehicular Technology, VOL. 48, No. 3, May 1999), by S. Kim, B. J. Guarino, Jr., T. M. Willis III, V. Erceg, S. J. Fortune, R. A. Valenzuela, L. W. Thomas, J. Ling, and J. D. Moore, (hereinafter xe2x80x9cRadio Propagationxe2x80x9d); xe2x80x9cAchievable Accuracy of Site-Specific Path-Loss Predictions in Residential Environments,xe2x80x9d (IEEE Transactions on Vehicular Technology, VOL. 48, No. 3, May 1999), by L. Piazzi and H. L. Bertoni; xe2x80x9cMeasurements and Models for Radio Path Loss and Penetration Loss In and Around Homes and Trees at 5.85 Ghz,xe2x80x9d (IEEE Transactions on Communications, Vol. 46, No. 11,November 1998), by G. Durgin, T. S. Rappaport, and H. Xu; xe2x80x9cRadio Propagation Prediction Techniques and Computer-Aided Channel Modeling for Embedded Wireless Microsystems,xe2x80x9d ARPA Annual Report, MPRG Technical Report MPRG-TR-94-12, July 1994, 14 pp., Virginia Tech, Blacksburg, by T. S. Rappaport, M. P. Koushik, J. C. Liberti, C. Pendyala, and T. P. Subramanian; xe2x80x9cRadio Propagation Prediction Techniques and Computer-Aided Channel Modeling for Embedded Wireless Microsystems,xe2x80x9d MPRG Technical Report MPRG-TR-95-08, July 1995, 13 pp., Virginia Tech, Blacksburg, by T. S. Rappaport, M. P. Koushik, C. Carter, and M. Ahmed; xe2x80x9cUse of Topographic Maps with Building Information to Determine Antenna Placements and GPS Satellite Coverage for Radio Detection and Tracking in Urban Environments,xe2x80x9d MPRG Technical Report MPRG-TR-95-14, Sep. 15, 1995, 27 pp., Virginia Tech, Blacksburg, by T. S. Rappaport, M. P. Koushik, M. Ahmed, C. Carter, B. Newhall, and N. Zhang; xe2x80x9cUse of Topographic Maps with Building Information to Determine Antenna Placement for Radio Detection and Tracking in Urban Environments,xe2x80x9d MPRG Technical Report MPRG-TR-95-19, November 1995, 184 pp., Virginia Tech, Blacksburg, by M. Ahmed, K. Blankenship, C. Carter, P. Koushik, W. Newhall, R. Skidmore, N. Zhang and T. S. Rappaport; xe2x80x9cA Comprehensive In-Building and Microcellular Wireless Communications System Design Tool,xe2x80x9d MPRG-TR-97-13, June 1997, 122 pp., Virginia Tech, Blacksburg, by R. R. Skidmore and T. S. Rappaport; xe2x80x9cPredicted Path Loss for Rosslyn, Va.,xe2x80x9d MPRG-TR-94-20, Dec. 9, 1994, 19 pp., Virginia Tech, Blacksburg, by S. Sandhu, P. Koushik, and T. S. Rappaport; xe2x80x9cPredicted Path Loss for Rosslyn, Va., Second set of predictions for ORD Project on Site Specific Propagation Predictionxe2x80x9d MPRG-TR-95-03, Mar. 5, 1995, 51 pp., Virginia Tech, Blacksburg, by S. Sandhu, P. Koushik, and T. S. Rappaport. These papers and technical reports are illustrative of the state of the art in site-specific propagation modeling and show the difficulty in obtaining databases for city environments, such as Rosslyn, Va. While the above papers describe a research comparison of measured vs. predicted signal coverage, the works do not demonstrate a systematic, repeatable and fast methodology for creating an environmental database, nor do they report a method for visualizing and placing various environmental objects that are required to model the propagation of RF signals in the deployment of a wireless system in that environment.
It is therefore an object of the invention to provide a method for manipulating drawings and electronic files to build databases for use in planning the positioning of components and for designing, installing and optimizing a wireless communication system. In the method, raster scanned images of an environment may be entered or object files in various formats may be used as input to define an environment in which a wireless system is to be implemented. Detailed information about the location, radio frequency attenuation, color, and other physical information of an object, such as intersections of the object with the ground, floors, ceilings, and other objects in the environment is stored in a drawing database.
It is another object of the invention to provide a computerized drawing in a true three-dimensional environment based on input data which is strictly two-dimensional in nature. The user sees the three-dimensional drawing structure on a computer display by altering the views.
It is another object of the invention to provide the resulting database of the inventive method in a form easily used in a variety of modeling applications, especially forms useful for engineering, planning and management tools for wireless systems.
It is another object of the invention to support a universal method for creating and editing and transporting environmental databases for wireless communication system design, prediction, measurement and optimization. A systematic and automated method for producing a 3-D environmental database that is reproduceable and transportable between many different wireless system prediction models, measurement devices, and optimization methods has value and is a marked improvement over present day systems.
According to the invention, pre-existing data for a desired environment may be scanned in, traced or translated from another electronic format as a short-cut to provide a partial definition for the environment. The partial or empty environment is then refined using a specialized drawing program to enter entities and objects that fully define the environment in terms of floors, partitions, obstructions, and other data required for engineering planning of a wireless communications network in the environment. The input data are generally two dimensional (2D) representations of the environment. When ceiling height, elevation above sea level, or partition height data is entered, the drawing may then automatically be viewed in three-dimensions (3D). This 3D representation enables the design engineer to visually verify any parameters incorrectly entered. The definition of the environment, or drawings, maps or other data are verified and the design engineer is automatically prompted to enter missing or inconsistent information. Once the drawing(s) have been verified, the data defining the environment may be used by a variety of tools, models, wireless propagation prediction methods, measurement products or optimization procedures that require information about an environment""s terrain levels, physical make up, and specific location of floors, walls, foliage or other obstruction and partition structures. Anything that impedes or otherwise affects the propagation of radio wave energy must be considered when predicting the performance of a wireless communication system in the environment, and the present methodology provides a simplified mechanism for collecting and editing this information in a readily usable form. The method for constructing and manipulating an indoor or outdoor environment is useful not only for wireless communication designers, but may also be useful for other applications, as well.